There are a few game series that Microsoft counts on heavily to sell consoles. The top two have to be Halo and Gears of War. We all know what’s happening in the Halo series with the remake of Halo: Combat Evolvedexpected November 15, and Halo 4 as the first game of a new trilogy arriving in 2012.

Gears of War 3 on the other hand is expected to release in September, but apparently you can play it today. In a leak that’s sure to frustrate both Microsoft and Epic Games, the game has started appearing on torrent sites for download. More specifically, an early build of the single-player campaign can be downloaded.

Proof of the game being available comes in the form of videos that have started appearing on YouTube. Some gamers are even recording complete walkthroughs of the campaign.

As the screenshots included here demonstrate, this build is far from the finished game and wireframe meshes appear throughout the levels as some form of placeholder or marker that acts as an in-game trigger.

Microsoft’s response so far has been to try and figure out where the game leaked from and to work with the authorities in tracking who uploaded the game to torrent sites. Regardless of whether that investigation ends up with an arrest, the game is now out and will be downloaded thousands of times.

The only good news for Microsoft is that this is an early build. While it may be playable, there is no multiplayer, there are aspects of the game missing, and those green wireframes will start to annoy shortly into a playthrough.